by Dan petrarca
(Newtown square, Pa.)
Kobalt 8 gallon compressor won’t power off when it reaches 150 psi
When the tank pressure reaches 150 psi, the unit is supposed to power off. It does not.
Instead, the pressure release valve releases the pressure, and the unit stays on. This happens over and over.
I replaced the pressure switch, but nothing changed.
Any thoughts?
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A thought about your Kobalt not powering off…
Unplug it…
Try removing one and then the other wire from the pressure switch. Make sure the wire can’t touch anything. Plug it in, turn it “on”. Does it run?
Please let us know.
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Kobalt 8 gallon compressor won’t power off.
My compressor does the exact same thing. I replaced the switch and same problem. I unplugged one of the wires, and yes it powers off.
What now?
Please let me know ASAP. Thank you.
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Kobalt 8 no turn-off by pressure
If you’ve already replaced the pressure switch, and it still doesn’t turn off, then either they are sending the wrong part, or the prv is bad and letting go too soon, before the tank pressure reaches the proper cut out setting.
Are there markings on the switch? Is the pressure actually going over 150, like 160 or so, before the prv lets go?
If the pressure is going high, then all I can tell you is to complain to the part source. What you are getting is either the wrong part, or a defective one.
Bill, I have the same problem. I switched out the pressure switch before checking your site. I then followed the steps outlined above and removed the wires one at a time and it doesn’t turn on if either of the wires are disconnected. What does that mean and what’s the fix? Thanks.
Jeff, the original post was about “Kobalt 8 gallon compressor won’t power off?”.
Is the issues with yours that it won’t start at all, even with the tank empty?
No it starts fine but won’t shut off when pressure is reached. I changed the pressure switch but it does the same thing.
If the compressor fills past the normal stopping point and you pull a wire off the pressure switch and the compressor stops, and you attach the wire again and the compressor starts again, even with air pressure in the tank higher than it should be (maybe by 5-10 PSI to allow for a wonkey pressure relief valve) then that points to the switch being the wrong spec, or failed out of the box.
The PRV opened up before it got 5-10 psi higher so I couldn’t really test it. When I pulled the wire it stopped but it was just below the shutoff pressure so I would assume that to be normal but I couldn’t really test it with the PRV opening up.
Watch the tank gauge as the tank is filling and as it nears the normal stopping pressure, use a gloved hand to hold the PRV shut and allow the pressure in the compressor to get 10 PSI past the normal cut out. If the compressor doesn’t stop it’s likely the pressure switch. If it stops on its own with the PRV held shut (only 10 PSI over normal cut out, no higher) then the PRV may be the problem.
I won’t be able to check it again until tomorrow at the earliest but the PRV operated before it was able to go above the pressure switch cut off pressure.
That sure suggests that the PRV may be the issue. Update the post when you can. Thanks.
It means the power is getting to the motor via the pressure switch, and not by a short somewhere. What happens if you let it run – does the PRV blow? What is the pressure when it stops building or the PRV lets go?
Are/were there marks on the box or pressure switch indicating cut-out pressure?
There are at least a couple variations of this – what’s your exact model number?
Doug, the PRV activates right about 150 psi, which is the designated shut off time marked on the pressure switch. The earliest I will be able to get a more specific model number is tomorrow. I think my original post has a model number of 0300841. If that helps.
Yeah, OK. Typically the PRV is rated a few pounds past cut-off, or sometimes a few below the tank rating.
If yours is marked say 160, then it’s blowing prematurely. You might want to try exercising and cleaning it, then retest.
I changed out the pressure switch and it seemed to work fine for a while but all of a sudden the PRV activated again and the switch didn’t cut-off. I haven’t run it that much, it’s been on a total of maybe 10 hours. I really don’t want to keep changing out pressure switches every time I use it a little while. Any thoughts?
Jeff, as stated previously, if the PRV is blowing before or just after rated cut-off of 150 PSI, then if cleaning and exercising the PRV was no help, replace the PRV.
If you’ve referenced the troubleshooting guide in the 0300841 manual, it is misleading in that it does not consider the possibility the the PRV might be bad, especially since they recommend testing it every use.
Anyone get this problem fixed ???
Jereme… please tell us what you found when you tried some of things written about on this page? Does it run until the PRV lets go, or does it run and run and not reach cut out pressure?
One more thought. Is there oil in the tank when you drain it? If so, oil may be blowing past the cylinder seal and entering the PRV, which would lubricate it some and allow it to blow off sooner than it should?